Deprecate function declarations, not definitions.

Also, switch to the [[]] style.

Bug: 289151149
Test: binder_rpc_test
Change-Id: I8ea37fec636237b9360c7db23e9018b8edce9622
diff --git a/libs/binder/include/binder/Parcel.h b/libs/binder/include/binder/Parcel.h
index 15bb325..b879650 100644
--- a/libs/binder/include/binder/Parcel.h
+++ b/libs/binder/include/binder/Parcel.h
@@ -265,7 +265,8 @@
     status_t            writeEnumVector(const std::optional<std::vector<T>>& val)
             { return writeData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
-    status_t            writeEnumVector(const std::unique_ptr<std::vector<T>>& val) __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            writeEnumVector(const std::unique_ptr<std::vector<T>>& val)
             { return writeData(val); }
     // Write an Enum vector with underlying type != int8_t.
     template<typename T, std::enable_if_t<std::is_enum_v<T> && !std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
@@ -275,17 +276,20 @@
     status_t            writeEnumVector(const std::optional<std::vector<T>>& val)
             { return writeData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && !std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
-    status_t            writeEnumVector(const std::unique_ptr<std::vector<T>>& val) __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            writeEnumVector(const std::unique_ptr<std::vector<T>>& val)
             { return writeData(val); }
 
     template<typename T>
     status_t            writeParcelableVector(const std::optional<std::vector<std::optional<T>>>& val)
             { return writeData(val); }
     template<typename T>
-    status_t            writeParcelableVector(const std::unique_ptr<std::vector<std::unique_ptr<T>>>& val) __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            writeParcelableVector(const std::unique_ptr<std::vector<std::unique_ptr<T>>>& val)
             { return writeData(val); }
     template<typename T>
-    status_t            writeParcelableVector(const std::shared_ptr<std::vector<std::unique_ptr<T>>>& val) __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            writeParcelableVector(const std::shared_ptr<std::vector<std::unique_ptr<T>>>& val)
             { return writeData(val); }
     template<typename T>
     status_t            writeParcelableVector(const std::shared_ptr<std::vector<std::optional<T>>>& val)
@@ -421,7 +425,8 @@
     status_t            readEnumVector(std::vector<T>* val) const
             { return readData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
-    status_t            readEnumVector(std::unique_ptr<std::vector<T>>* val) const __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            readEnumVector(std::unique_ptr<std::vector<T>>* val) const
             { return readData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
     status_t            readEnumVector(std::optional<std::vector<T>>* val) const
@@ -431,7 +436,8 @@
     status_t            readEnumVector(std::vector<T>* val) const
             { return readData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && !std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
-    status_t            readEnumVector(std::unique_ptr<std::vector<T>>* val) const __attribute__((deprecated("use std::optional version instead")))
+    [[deprecated("use std::optional version instead")]] //
+    status_t            readEnumVector(std::unique_ptr<std::vector<T>>* val) const
             { return readData(val); }
     template<typename T, std::enable_if_t<std::is_enum_v<T> && !std::is_same_v<typename std::underlying_type_t<T>,int8_t>, bool> = 0>
     status_t            readEnumVector(std::optional<std::vector<T>>* val) const
@@ -442,8 +448,9 @@
                             std::optional<std::vector<std::optional<T>>>* val) const
             { return readData(val); }
     template<typename T>
+    [[deprecated("use std::optional version instead")]] //
     status_t            readParcelableVector(
-                            std::unique_ptr<std::vector<std::unique_ptr<T>>>* val) const __attribute__((deprecated("use std::optional version instead")))
+                            std::unique_ptr<std::vector<std::unique_ptr<T>>>* val) const
             { return readData(val); }
     template<typename T>
     status_t            readParcelableVector(std::vector<T>* val) const